“…With this in mind, the present Special Issue of Applied Sciences on "Federated and Transfer Learning Applications" provides an overview of the latest developments in this field. Twenty-four papers were submitted to this Special Issue, and eleven papers [1][2][3][4][5][6][7][8][9][10][11] were accepted (i.e., a 45.8% acceptance rate). The presented papers explore innovative trends of federated learning approaches that enable technological breakthroughs in highimpact areas such as aggregation algorithms, effective training, cluster analysis, incentive mechanisms, influence study of unreliable participants and security/privacy issues, as well as innovative breakthroughs in transfer learning such as Arabic handwriting recognition, literature-based drug-drug interaction, anomaly detection, and chat-based social engineering attack recognition.…”